Wick having liquid superheat tolerance and being resistant to back-conduction, evaporator employing a liquid superheat tolerant wick, and loop heat pipe incorporating same

• US 20050252643A1
• Filed: 06/28/2005
• Published: 11/17/2005
• Est. Priority Date: 05/16/2000
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Swales & Associates, Inc.
• Inventors: Kroliczek, Edward J., Wolf, David A. Sr., Wrenn, Kimberly R.
• Granted Patent: US 8,397,798 B2
• Time in Patent Office: Days
• US Class Current: 165/104.260
• CPC Class Codes: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28D 15/04 with tubes having a capillary structure
• CPC Class Codes: F28D 15/043 forming loops, e.g. capillary pumped loops
• CPC Class Codes: F28D 15/046 characterised by the material or the construction of the capillary structure
• CPC Class Codes: Y10T 29/49353 Heat pipe device making

Abstract

A two-phase heat transfer system includes an evaporator, a condenser, a vapor line, and a liquid return line. The evaporator includes a liquid inlet, a vapor outlet, and a capillary wick having a first surface adjacent the liquid inlet and a second surface adjacent the vapor outlet. The condenser includes a vapor inlet and a liquid outlet. The vapor line provides fluid communication between the vapor outlet and the vapor inlet. The liquid return line provides fluid communication between the liquid outlet and the liquid inlet. The wick is substantially free of back-conduction of energy from the second surface to the first surface due to an increase in a conduction path from the second surface to the first surface and due to suppression of nucleation of a working fluid from the second surface to the first surface to promote liquid superheat tolerance in the wick.

Claims

1. An evaporator comprising:

a liquid inlet;

a vapor outlet;

a capillary wick having a first surface adjacent the liquid inlet and a second surface adjacent the vapor outlet,

wherein the capillary wick is substantially free of back-conduction of energy from the second surface to the first surface due to an increase in a conduction path from the second surface to the first surface and due to suppression of nucleation of a working fluid from the second surface to the first surface to promote liquid superheat tolerance in the wick.

2. The evaporator of claim 1, wherein pore size is substantially uniform between the first surface and the second surface.

3. The evaporator of claim 1, wherein pore size is graded between the first surface and the second surface.

4. The evaporator of claim 1, wherein the capillary wick is free of any internal liquid flow channel.

5. The evaporator of claim 1, wherein the capillary wick has substantially cylindrical geometry.

6. The evaporator of claim 1, wherein the capillary wick has substantially flat geometry.

7. The evaporator of claim 1, wherein the evaporator operates reliably in a terrestrial gravitational field.

8. The evaporator of claim 1, wherein the capillary wick is formed of a polymer resin.

9. The evaporator of claim 8, wherein the capillary wick is formed of polytetrafluoroethylene.

10. The evaporator of claim 1, wherein the capillary wick is formed of metal.

11. The evaporator of claim 1, further comprising vapor grooves in fluid communication with the vapor outlet;

wherein pore size within the capillary wick is configured to suppress nucleation of the working fluid between the first surface and the second surface.

12. A two-phase heat transfer system comprising:

an evaporator having a liquid inlet, a vapor outlet, and a capillary wick having a first surface adjacent the liquid inlet and a second surface adjacent the vapor outlet;

a condenser having a vapor inlet and a liquid outlet;

a vapor line providing fluid communication between the vapor outlet and the vapor inlet; and

a liquid return line providing fluid communication between the liquid outlet and the liquid inlet;

wherein the wick is substantially free of back-conduction of energy from the second surface to the first surface due to an increase in a conduction path from the second surface to the first surface and due to suppression of nucleation of a working fluid from the second surface to the first surface to promote liquid superheat tolerance in the wick.

13. The two-phase heat transfer system of claim 12, wherein the evaporator includes vapor grooves in fluid communication with the vapor outlet;

wherein pore size within the wick suppresses nucleation of the working fluid between the first surface and the second surface.

14. The two-phase heat transfer system of claim 13, wherein pore size is substantially uniform between the first surface and the second surface.

15. The two-phase heat transfer system of claim 13, wherein pore size is graded between the first surface and the second surface.

16. The two-phase heat transfer system of claim 12, wherein the wick is free of any internal liquid flow channel.

17. The two-phase heat transfer system of claim 12, wherein the wick has substantially cylindrical geometry.

18. The two-phase heat transfer system of claim 12, wherein the wick has substantially flat geometry.

19. The two-phase heat transfer system of claim 12, wherein the wick is formed of a polymer resin.

20. The two-phase heat transfer system of claim 19, wherein the wick is formed of polytetrafluoroethylene.

21. The two-phase heat transfer system of claim 12, wherein the wick is formed of metal.